I am going to strip off the bottom forward of the step all the way to the chine and add some stringers. Then cover with ply, epoxying the whole inside while applying. Then glassing the outside. I will add foam too just in case. I found some foam for sealing windows that comes in an aerosol can. It doesn't expand to the point of making pressure and won't hurt the floats. Probably won't add 2 oz. While repairing the bottom, I might as well go through the entire float to clean up the detail.